Pretty much agree with the other posts here. It'd be nice if unlocking this gave you some kind of laser designator amongts your weapons, that you could aim at more distant targets. It wouldn't need to be sniper rifle range or anything, but having to run up and throw a flare and then hope your opponents stay in place a while AND hope the tiny aoe on the explosions kills anyone is a bit much.
Several of the Merryweather unlocks sound cool, but none are as effective as you'd hope. I've used the helicopter pickup a couple of times I guess. Only really useful if you end up a LONG way from a road, otherwise it's faster to drive than wait for the guy to come in, land, fly slowly to your waypoint, then negotiate the parachute jump down.